Method and apparatus for false twisting yarn



Jan. 15, 1957 N. E. KLEZN METHOD AND APPARATUS FOR FALSE TWISTING YARNFiled May 11, 1953 1 ball- INVENTOR flrmzvZf/fl9akg 1/45; @4, yaw wwATTORNEYS United States Patent Ofitice 2,777,276 Patented Jan. .15, 1957Norman E. Klein, Pendleton, S. C., assignor to Deering Milliken ResearchCorporation, Pendleton, S. C., a corporation of Delaware Application May11, 1953, Serial No. 353,950

6 Claims. (Cl. 57-773) This invention relates to the processing offilamentary textile materials and is more particularly directed to animproved method and apparatus for false twisting strands of textilematerial, having particular utility in the production of crimped effectstherein.

It has been known for a considerable period of time in the textile artthat crimped effects could be imparted to textile strands by twistingsuch strands to a high degree of twist, setting the twist therein, andthereafter untwisting the strand. It has been also suggested bypriorpatents that the steps of twisting and untwisting in the above processcould be practiced simultaneously by means of a false twister. At thetime it was made, this latter suggestion was viewed with considerableinterest by the workers in this art since it apparently presented vameans by which the separate and costly steps of supertwisting anduntwisting could be dispensed with. However, in so far as I am aware,the possibilities which the improved method possessed, at least from atheoretical aspect, have not been realized when the method was adaptedfor commercial production. Apparently, this has been due to the factthat in the false twisters heretofore known in the, art, the means bywhich the yarn was frictionally engaged in order to obtain the purchaseor grip thereon necessary for rotating it about its axis were soconstructed that the yarn just approaching the frictional engaging meanslaterally abutted or contacted the yarn just leaving such means with theresult that portions of the yarn rubbed against each other, causingbroken filaments, stripped-back filaments, and other similar defects,none of which can be tolerated in any number in a piece of finishedfabric. The arrangement which was adopted almost without exception bythe prior art to obtain the necessary purchase on the yarn consistedessentially of a cylindrical pin or a grooved pulley mounted forrotation about a transverse axis, one convolution of the yarn beingwrapped around the pin or pulley. Thus, the laterally adjacent portionsof the convolution rubbed against each other as the yarn was drawnaround the pin or pulley, damaging the yarn in the manner justdescribed.

The primary object of the present invention is therefore to provide amethod and means for false twisting yarn in which the portions of theyarn passing through the twister are maintained in non-contactingrelationship.

A further object of this invention is to provide an improved method andmeans of falsetwisting yarn in which the yarn engaging means is sodisposed that the portion of the yarn just approaching said means doesnot contact the portion of the yarn just leaving said means.

Other and further objects and advantages will be ap' parent from thefollowing detailed description when read Figure 3 is a fragmentaryelevation of a modified form of the improved twister and Figure 4 is aview essentially diagrammatic, for the preferred arrangement forpracticing the method of the present invention.

The apparatus which itself forms a part of the present invention andwith'which the method of the present invention is practiced isillustrated in Figures 1 and 2. In these figures the'numeral lldesignates a tubular stator member having a threaded lower portion 13.At the end of the stator member 11 remote from the threaded portion 13is a section of enlarged diameter or crosssection 15 in which there isformed a socket or recess 17. Press fitted into the recess 17 is theouter race 19 of an oil-sealed anti-friction bearing, generallydesignated 21 of the type capable of withstanding high speed rotation ofthe order of 20,000 to 40,000 R. P. M. Supported by the inner race 23 ofthe anti-friction bearing 21 is a tubular rotor member 25 having at itslower end a portion of reduced cross section 27 which is press fittedinto inner race 23. The tubular rotor member 25 is preferably mounted inco-axial relationship with the tubular stator member 11 with the boresextending through the respective lengths of the tube member being insubstantial registration.

There is formed in the distal or upper end of the rotor member 25 a pairof diametrically opposite slots 29 and 29', extending from the upperface of the rotor member 25 into the body of the same for a portion ofits length. Supported by the portion of the walls of the rotor 25 oneither side of the pair of slots 29 and 29' is a cylindricalcross-member or pin 31, the ends of which fit into suitable aperturesprovided in the rotor walls, being secured therein in any desiredmanner. As can be seen from Figures 1 and 2, the cross member 31 extendssubstantially diametrically across the rotor member 25, traversing thebore thereof, being preferably at right angles to the plane of the slots29 and 29' with its longitudinal axis slightly inclined or obliquelydisposed with respect to the longitudinal axis, i. e., the axis ofrotation, of the rotor member 25. Preferably, the portions of thecross-member 31 on either side of the rotor axis are tapered in thedirection of such axis so as to provide a central necked down portion 33on the cross-member 31 which is adapted to have a single convolution ofyarn wrapped therearound. The function of the necked down portion 33 isto center the yarn on cross-member 31 and in connection with theaccompanying drawings in which 1 reduce the ballooning action of theyarn while it is being rotated at high speed.

The manner in which my improved false twister is threaded up for actualoperation may be described as follows: One end of a strand offilamentary textile material of relatively great length is attached tothe end of a flexible snake in a fashion well known in the art. Thesnake is then inserted into the lower end of the bore of stator member11 and drawn vertically up through both of members 11 and 25, the yarnbeing drawn with it and eventually passing completely through thedevice, lying on one side or the other of cross-member 31. The snake isthen moved over to one side of the twister, so that the yarn lies aroundthe top of cross-member 31, and inserted into one of the slots, say, 29,passed horizontally underneath cross-member 31 and out through the otherslot, 29. Following this, the yarn can be removed from the snake andattached to any suitable col lection means. At this point the yarnextends axially through the twister, having one convolution wrappedaround the pin 31. The collection means may now be actuated and rotationimparted to the rotor member 25 in any desired manner, and as the yarnis drawn through the device, twist is inserted therein on the input sideof 3 cross-member 31 and removed therefrom on the output side ofcross-member 31.

In Figure 3 there is shown a modified form of the improved false twisterin which a cross-member 31' is formed in the shape of an inverted L, thelong leg of the L being inserted in a vertical recess 35 provided in theupper face of a rotor with the short leg extending across the bore ofthe rotor. slightly inclined from the horizontal similar to member 31 inFigures 1 and 2 and is also necked down, as at 33', the terminationthereof being preferably of enlarged bulbous shape to confine the yarnthereon. The modified version operates in substantially the same fashionas does the first described form with the exception that it is easier tothread up since the yarn need not be insorted through the rotor slot butcan merely be wrapped around the member 31.

The essence of my improved false twister by which it differs from thefalse twisters heretofore known in the art resides in the inclination ofcross-member 31 with respect to the axis of rotation of stator 25, whichis, of course, also the axis of rotation of cross-member 31, since thecross-member forms a part of rotor 25; ticular angle at which the pin isdisposed may be varied considerably without departing. from theinvention. In general, it is not necessary to resort to the use ofexcessively large angles and I have had good success using an angle offrom about'5 to about 15 degrees, substantially as illustrated in Figurel.

The inclination of the pin accomplishes the rseult of urging thelaterally adjacent portions of the yarn convolution apart in thefollowing manner: Since the tension in the input portion of the yarnconvolution, that is, the portion just approaching the pin, acts in anessentially downwardly direction, this portion tends to move toward thelower end of the pin and, correspondingly, since the tension in theoutput portion of the convolution The short leg is, of course Theparacts essentially upwardly, this portion tends to move toward theupper end of the pin. Thus, the normally adjacent portions of theconvolution tend to be maintained apart and there is little or noopportunity for them to rub against each other. In accordance with thistheory, it is highly desirable to so carry out the threading up of thefalse twister that the input side of the convolution is on the lowerside of the pin while the output side of the convolution is on the upperside of the pin.

The method of the present invention, in its broadest aspects,contemplates the feeding of a strand of filamentary textile material toa longitudinal member rotating about a substantially transverse axiswhich may be either co-axial with or parallel to the path of the yarn,the member having its longitudinal axis inclined or obliquely disposedwith respect to such axis of rotation, wrapping at least one convolutionof the strand around the longitudinal member and withdrawing the strandfrom the longitudinal member. However, since this phase of my inventionhas been found to have particular utility as a part of a method forcrimping yarn and since this method is representative of the successfulpractice thereof, this latter phase will be described and illustrated inconnection therewith although, as will be readily appreciated, it is byno means limited thereto inasmuch as it is capable of application towidely varying end uses.

In Figure 4, the numreal 41 designates a yarn supply package, such as apirn, bobbin, cake or the like, from which a single strand of yarn isunwound and passed through a disc tension device 43 of the type wellknown in the art. From the tension device 43, the yarn travels upwardlypast one side of a polished chromium plated heater element 45 connectedby electrical leads 47 and 47' to a suitable source of alternatingelectric current, thence through the false twister unit 48, the detailsof which have already been described, and finally to a take-up package,generally designated 49, which may conveniently take the form of ametal-flanged bobbin driven by a rotating cork-covered roll 53. Thetwister unit 48 may be supported in any desired fashion but I have foundit expedient to associate the false twister unit with the conventionalspindle bolster of an Atwood M-lOO up-twister. 55 indicates such abolster, having a vertical aperture therethrough penetrated by thetubular stator member 11 of the false twister unit. The lower face ofthe enlarged portion 15 rests against the upper face of the bolster andthe portion of the body of the stator 11' disposed below the bolster isencircled by a compression spring 57, which beans at its upper endagainst the lower face of bolster 55 and at its lower end against a nut59 threaded on the lower portion 13' of stator 11.

The function of heater element 45 is, of course, to soften the yarn sothat as it is later twisted by the false wister unit 43 it sets orhardens in its twisted configuration. in broader terms, its purpose isto place the yarn in such a state or condition that it may be later setin a given configuration. While, in most instances, an electric heaterstrip is the simplest and cheapest means of accomplishing this function,obviously, other means could be employed if desired. For example, asteam chamber could be utilized, the yarn passing through such chamberbefore its delivery to the false twister unit or,

alternatively, the yarn could be impregnated with one of a number ofwell known resinous setting agents, such as urea formaldehyde, melamineformaldehyde, or the like. Again, compounds for producing swellingresistance could be applied to the yarn, as is disclosed in Patent2,463,618. Broadly, therefore, the presentinvention embraces any and alltreatments by which yarn may be caused to retain a particularconfiguration. The particular conditions at which the various treatmentsshould be carried out are well within the skill of the art and willnotbe described in detail.

By the proper selection of the means for treating the yarn as justdescribed, yarns of widely varying character and composition may beprocessed in accordance with my invention. Where the yarn is heatedprior to its passage through the false twister unit by means of anelectric heater or a steam chamber, I have found the best results areobtained with yarns which are thermo plastic it. character, includinglinear polyamides, derivatives of cellulose, polyesters of ethyleneglycol and terephthalic acid, polymers consisting in whole or in part ofacrylonitrile, and polyvinyl resins and copolymers of the same. On theother hand, where the use of chemical treatments are contemplated, mymethod may be applied with equal facility to natural and regeneratedcellulosic fibres as well as those based on proteinaceous materials.

In .theusual case I prefer that the yarns which are to be processed inaccordance with my improved method should be of the continuousfilamentary type, that is, the individual filaments which are groupedtogether to comprise the yarn are substantially continuous in theirlength. However, under certain circumstances my invention may bemodified or used with staple fibre yarns. This can be accomplished, forexample, where two or more staple fibre yarns are processed together, i.e., either in side-by-side relationship or in the form of a plied yarn.The desired result may also be achieved provided the staple fibre yarnis initially twisted to a point where the discrete fibres aresubstantially cohesive and provided further that the twist inserted bythe false twisting unit is in the direction of the twist initially inthe yarn so that the yarn never passes through a point of zero twist.

From the above, it will be apparent to those skilled in the art that Ihave provided an improved method and means by which false twist may becontinuously inserted and removed in a moving strand of yarn withoutrendering the yarn defective by reason of broken filaments, strippedbackfilaments and the like.

The foregoing description of specific embodiments of the related aspectsof my invention is set forth by way of example only, and it is in no wayintended that the invention is limited to the specific features thereofbut only by the spirit and scope of the claims hereunto appended.

Having thus described my invention, that which is claimed is:

1. A false twister spindle comprising a tubular stator member, a tubularrotor member rotatably carried by said stator member in coaxialrelationship therewith, and a pin diametrically mounted in'said rotormember, said pin having its axis inclined with respect to the commonaxis of said stator and rotor members, and said pin having a centerportion of reduced diameter.

2. A false twister spindle comprising a tubular stator member, a socketof enlarged section at one end of said member, an anti-friction bearinghaving an inner and outer race, the outer race being received by saidsocket, a tubular rotor member coaxial with said stator member, aportion of reduced cross-section at one end thereof, said portionengaging said inner race, and a cross-member diametrically mounted insaid rotor member, having its longitudinal axis obliquely disposed withrespect to the axis of said rotor member, the center portion of saidcross-member being of reduced cross-section.

3. In a method of false twisting yarn, the improvement which comprisesforming and maintaining a single loop in a substantially straight lengthof a moving strand of said yarn, retaining adjacent sections of yarn insaid loop out of contact by positioning said loop in a plane which is atan angle to said straight length such that the tension in the strandentering and departingsaid loop tends to open the same, and rotatingsaid loop about the longitudinal axis of said straight length.

4. A false twist spindle comprising a rotatable cylindrical memberhaving an axial bore adapted to receive a moving strand of filamentarytextile material, said cylindrical member having a pair oflongitudinally extending diametrically opposed slots, said slots, ineach instance, being open ended at one end of said cylindrical member, across-member, with a center portion of reduced diameter, extendingacross said bore, said cross-member having its longitudinal axisinclined with respect to the axis of said bore and said cross-memberhaving opposite ends supported by the opposed sections of saidcylindrical member between said slots, whereby a threading tool can bepassed through said slots inwardly of said cross-member subsequent tobeing passed through said axial bore to result in a yarn end beinglooped around said crossmember.

5. A false twister spindle comprising a rotatable cylindrical memberhaving an axial bore therein adapted to receive a moving strand offilamentary textile material and an elongated yarn engaging elementcarried by said member, said elongated element having a first sectionextending longitudinally of said cylindrical member from one end thereofand said elongated element having a second section extending from saidfirst section substantially across the extended axis of rotation of saidrotatable member with the longitudinal axis of said second sectioninclined with respect to the axis of said bore, said second sectionhaving an unsupported end and a center portion of reduced diameter,whereby a loop in a strand, passed through the axial bore in saidrotatable member, can readily be passed over the free end of said yarnengaging element and is thereafter retained in position by said portionof reduced diameter.

6. A false twister spindle comprising a rotatable member having an axialbore therein to receive a moving strand of filamentary material, across-member carried by said rotatable member, said cross-member havingits longitudinal axis inclined with respect to the axis of said bore,and loop positioning means to retain a loop, formed in said movingstrand of material and placed about said cross-member, in such aposition that said loop lies generally in a plane which is at an obliqueangle to the axis of rotation of said rotatable member, whereby thetension in the yarn entering and departing said loop retains adjacentportions of the yarn in said loop out of contact with each other.

References Cited in the file of this patent UNITED STATES PATENTS633,964 McMichael Sept. 26, 1899 1,728,414 Jowett et al. Sept. 17, 19291,772,109 Quaas Aug. 5, 1930 1,830,728 Wiese Nov. 3, 1931 1,847,582Wenzel Mar. 1, 1932

